JotForm is a free online form builder which helps you create online forms without writing a single line of code. No sign-up required.
We believe that if one user has a question, there could be more users who may have the same question. This is why many of our support forum threads are public and available to be searched and viewed. If you’d like help immediately, feel free to search for a similar question, or submit your question or concern.
You can use the ticket purchase widget: https://widgets.jotform.com/widget/ticket_purchases
Where you will need to create conditions to calculate the total in a text box field: https://www.jotform.com/help/268-How-to-Insert-Text-or-Mathematical-Calculation-into-a-Field-Using-Conditional-Logic
And if you want to pass the total to a payment field, here is how: https://www.jotform.com/help/275-How-to-Pass-a-Calculation-to-a-Payment-Field
Let us know if you need more help, we will be glad to assist you.